Patent GB-190721692-A (GB)
Title: Improvements in or relating to Photographic Films and Film Packages.
Inventor: THORNTON JOHN EDWARD
Filed: 1907-10-01
Granted: 1908-10-01
Abstract: 21,692. Thornton, J. E. Oct. 1. Developing; fixing; washing; sensitized plates and films; change-boxes; envelopes; dark-slides; plate and like boxes; roller slides; trays and dishes. -Daylight-loading packages of films are developed, fixed, and washed in daylight without any preparation after leaving the camera. The packing case or spool is provided with light-tight water vents, and the layers of films are separated to form a passage for liquid, an absorbent backing or wrapper being used between the films. The package may contain the developing and fixing chemicals in a convenient manner, and the packing - case may serve as the developing- tank. The water vents in the spool are formed by two perforated disks h,. Fig. 17, with a baffle-plate h<1> between, or the plate h<1> may be replaced by a pad of absorbent material such as felt &c., or this material may be used without the disks h, or the liquid may enter at the edge. only one disk h being perforated, Fig. 19. The baffle-plate may be omitted, flanges on the disks being made to overlap and trap the light, or the flanges may be brought together and the end disks placed with the perforations non-coincident ; or, according to the Provisional Specification, a disk of absorbent material may be clamped to a single perforated disk. The water vents for flat films may be similar but in one or more sides or edges of the packing - box. The water spaces between the film layers may be formed by the film or backing or interleaves. Their edges may be thickened and serrated and cut away at intervals, or thickened by additions thereto ; or the edges may be crimped, Fig. 36, or teeth or dots may be raised by passing, between suitable embossing-rollers. Between each film layer is placed a developing-wrapper D, Fig. 35, which is attached to roll films at each end of the roll, and to flat films by the usual means, when it also carries the numbered pull tabs. This wrapper D is made of a thick sheet or of several thin sheets of absorbent material, for example unsized bibulous paper such as filter or blotting paper, textile material such as woollen or cotton cloth, hygroscopic colloids such as gelatine or agar-agar, or any of these materials in combination ; or, according to the Provisional Specification, lamp-wick materials or swansdown may be used. This wrapper absorbs the developing &c. liquid and distributes it evenly over the face of the film in contact ; it is preferably formed with fine distributing channels, either in one or all of the component sheets, in the shape of cross or diagonal corrugations, curved or circular lines overlapping each other, or a series of raised dots, all very near together, Figs. 40 and 45. To prevent the wrapper from marking the film, it may be attached to one or two plain sheets d, Figs. 42 and 44, of absorbent material acting to diffuse the liquid by laying it upon a plain sheet bearing cement or upon a sheet of gelatine before it has set or dried. The wrapper may be attached to the film by a soluble cement such as gum, and should be stiff enough to retain a set; as a precaution against damp, the ends of the wrapper may, according to the Provisional Specification, be made waterproof and non-absorbent, and the spool flange may be dispensed with by leaving the wrapper wider than the film and turning its edges. The films may be provided with layers of developer and opaque colouring-matter, of anti-curling gelatine, or with layers a<2>, Fig. 52, of sensitive emulsion, a<1> of transparent celluloid base, a<4> of anti - curling gelatine, a<8> of soluble cement, and D of developing- wrapper, a<9> being a loose sheet of diffusing absorbent material. The indicating-numbers or marks are formed in the developing - wrapper or opaque layer, being woven in a different coloured thread in the case of textile material, or being stained with inert dye in the case of paper or gelatine. The film roll or pack is developed by being immersed bodily in a tank of solution in daylight. The chemicals are preferably contained in the film package either as a paste or as a solution soaked in and dried in the following ways : to the film base or anti - curling layer ; to the opaque or developing.wrapper either fixed to or free from the film ; or to the carrier or packing-case. The chemicals may be contained as a soluble capsule in the hollow core of the spool attached to the inner end of the spool wrapper, being the outer end after exposure, or inside the enclosing-case, as between the plates of the central division of the case of a film pack. Chemicals for fixing and hardening may also be contained; a combined developer and fixer, such as pyrocatechine with sodium or ammonium hyposulphite, is used, or the developing - chemicals are at once dissolved and the fixing-chemicals protected for a time. For the latter purpose, the chemicals may be in soluble capsules, the fixing-capsules dissolving much later than the developer as by the varying thickness of the walls of the capsule ; or the fixer may be packed in the tube or case and protected by plugs of gelatine, wool, paper, &c., the developer being packed, and protected only by a paper label or wool plug, by which water may gain quick access ; or the developer may be placed in one end and the fixer in the other, the water not quite covering the case, which is inverted to complete the process ; or the cap may contain the fixer G, Fig. 28, and may be removed while the case M with the developer F is filled with water, and replaced when required. According to the Provisional Specification, the chemicals may be placed in an adaptor or inner tube inside the spool, or the end of the wrapper may be rolled to form the spool core and contain the chemicals. A convenient tank for developing and fixing consrsts of a case or tube M, Fig. 30, just large enough to take the film package. The tank may be arranged with a rubber adaptor nz, and a clip, threaded screw, or other device for attachment to a water tap, and may have an outlet as well, the washing being expedited by attaching the tank to an air-pump to force air through or expel air from the tank. According to the Provisional Specification a pressure pump may be used, and for daylight washing the film may be passed through a wringer into a water bath. The outer packing-box may be of metal, or may be waterproofed and used as the tank M to develop, fix, and wash the films. One end may be closed, and the other end may have a lid screwed or fitted on, and made water - tight with a rubber or other flexible packing-pad; or both ends may be removable and one or both may be replaceable by a washing attachment m. According to the Provisional Specification, the invention relates also to films or plates in change-boxes, envelopes, or darkslides, to colour plates or films, and to non-daylight loading systems. Specifications No. 4955, A.D. 1898, Nos. 17,292 and 17,737, A.D. 1899, and Nos. 11,033, 11,884, 12,003, and 21,189, A.D. 1906, are referred to.